


Beginnings

by BlueNeutrino



Series: Isosceles Triangles [1]
Category: Supernatural
Genre: Anal Sex, Blow Jobs, Bottom Dean, Face-Fucking, First Time, First Time Topping, Gags, Light Bondage, M/M, Multi, Porn with Feelings, Sibling Incest, Spitroasting, Threesome - M/M/M, Top Castiel, Top Sam, Wincestiel - Freeform
Language: English
Status: Completed
Published: 2014-07-29
Updated: 2014-07-29
Packaged: 2018-02-10 23:43:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,867
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2044638
Author URL: https://archiveofourown.org/users/BlueNeutrino/pseuds/BlueNeutrino
Summary: <blockquote class="userstuff">
              <p>Mini-prequel to “Share Alike” showing how Cas became involved in Sam and Dean’s existing relationship and how their three-way dynamic got started.</p>
            </blockquote>





	Beginnings

**Author's Note:**

> I don’t like writing smut with Cas if Jimmy’s still rattling around in the vessel somewhere, so since I subscribe to the belief that Jimmy died when Cas got blown up the first time, this is taking place in season five.

A frown creased Cas’ brow, confusion etched on his features while he tried to make sense of the scene in front of him. The motel room they were in was cheap and shabby, just like the usual, but what the brothers were doing was most definitely _not_ usual, Cas thought. Dean was laid out on the bed, completely naked with his hands tied to the headboard and a gag in his mouth, and Cas noticed his penis was also erect. Sam was hovering over him, still wearing his jeans but otherwise naked from the waist up, and was staring steadily at Cas as he waited for the angel to process what he was being shown.

Cas cocked his head to the side and scrutinised Sam intently. He was trying very hard to understand what the younger Winchester had just attempted to explain. “So…you enjoy sex with him?” he asked curiously, his gaze scanning over Dean’s naked form and taking in his state of arousal before returning to Sam’s face.

The younger brother nodded. “Yes,” he stated plainly.

Cas was still a little confused. “Is it not usually frowned upon for brothers to partake in this kind of activity?”

Sam shrugged, seeming to think that was no issue. “Maybe. But we’re both consenting adults, there’s no risk of us having children, and honestly, it’s no-one else’s business. We do this because we enjoy it.”

“If it’s no-one else’s business, then why are you showing me?”

“We wanted to know how you felt about it,” Sam replied, a smile playing on his lips.

“I…” Cas began to answer, and then trailed off. He wasn’t sure how he felt about it. Truthfully, there was nothing about it he found repellent, but it was taking him a while to adjust to seeing Dean like this. Normally, whenever Dean was tied up it was because he was in danger, and it would be Cas’ first instinct to go and free him, but now he seemed…content. That was the best way Cas could describe the expression on Dean’s face. He looked happy. Excited, even, and he was of course safe with Sam. Cas found that pleasing, even though he still didn’t quite understand why. “I’d like to know why Dean is tied up,” he asked.

“That’s because Dean is a submissive,” Sam replied patiently. “He likes to be dominated, and I like to dominate him. For us, it’s an expression of love.”

Maybe, Cas thought, he was beginning to get it. He saw the appeal of doing things that the person you loved enjoyed. “So you do this because you love him?”

Sam nodded again. “That’s right.”

That was interesting. Cas had come to understand that there were many different ways for humans to express their sexuality and they each enjoyed many different things, but he’d never before realized that this would be one of Dean’s preferences. He was about to ask for more details when Sam continued. “Do _you_ love him, Cas?”

The question took him by surprise. “What?”

“Do you love him?” Sam repeated. “I know that you kissed him. He told me.”

Cas held his tongue, still unable to find the best response. That was true, about the kiss. It had been a crazy, slightly inebriated moment of passion, when they’d been about to take on Raphael and didn’t know if they’d survive and it just seemed like the thing to do…but then not long after they’d gone their separate ways again, Sam and Dean had reunited and begun to make up, and they hadn’t spoken about it since. Except that now, Dean had clearly said something, and it was Sam bringing it up.

Again, Sam repeated the question. “What I – what we both – want to know, is if that means you love him?”

In the end, all Cas could do was answer honestly. “Yes,” he stated bluntly. “I do.” It was the plain and simple truth. He’d come to realise that he would do anything for Dean, no matter what the cost to himself, and it could only be because he’d come to love the human more than he’d once believed was possible.

At the angel’s answer, Sam smiled warmly and then turned his gaze onto Dean, reaching up a hand to gently caress the side of Dean’s face. “You hear that, Dean? Cas loves you. Do you love him back?”

Dean twisted his head, fixing his eyes on Cas as he answered with an emphatic, purposeful nod.

Cas’ heart skipped a beat. He couldn’t help but think he’d rather have heard it in Dean’s voice, from Dean’s lips, and not at a prompt from Sam, but just the knowledge that Dean loved him too was enough to send of surge of warmth coursing through him. A broad smile spread across his face.

“There you are,” Sam continued, still gently stroking Dean’s cheek. “Dean loves us both, and we both love him. So now what we want to ask is, do you want to join us?”

Still feeling a little giddy with happiness, Cas met Sam’s gaze again. A swirl of uncertainty had mixed with the joy inside him, although he was beginning to feel excitement too. “I, uh…I don’t know…”

“Cas, I don’t want to leave you out,” Sam reassured, noticing his hesitation. “Not if this could make us all happy.”

“Sam, I don’t have much experience with sexual situations,” Cas admitted, embarrassed. “I don’t know what he’d like.”

“That’s alright, Cas. That’s why I’m here to show you.” Sam was holding out a hand to the angel, inviting him to join him by the bed, and the look on his face was open and affectionate.

As he saw the way Sam was looking at him, Cas felt his insecurities melt away. He wanted to make Dean happy, and if there was one person who could show him how to do that, it was Sam. “Alright,” Cas said, accepting the offered hand as he walked to stand beside the younger Winchester. “What shall I do?”

Sam cast his gaze up and down the angel’s still-clothed body. “Well, first, he’d like to see you naked,” he answered, reaching down to his own jeans and undoing his own zipper. “You’ve gotten to look at him naked, so let him get a good look at you too. I’m sure he’d enjoy that.” A faint moan from Dean on the bed confirmed that he would.

Hesitating, Cas glanced over at him and then back at Sam, who had pushed his own jeans and boxer briefs down to his ankles and stepped out of them. With both brothers now completely undressed, Cas saw that both their penises were hard and leaking. Not wasting any more time, with a thought, Cas’ own clothes were suddenly removed and banished to a pile a short way away.

Sam blinked at him, a little amused by Cas’ choice to use his angel powers. It would perhaps have been more of a tease for Dean to have Cas strip down slowly in front of him, but this worked and got things moving quickly. “Alright,” Sam said, gazing down at Cas’ body and finding it was an enjoyable sight. “If you want to have some fun with him, you’ll need to get hard. Can you do that?”

“I don’t really know,” Cas answered. This was all unfamiliar to him, but he noticed his own penis wasn’t getting stiff like Sam and Dean’s were.

“Okay, try this,” Sam said helpfully. “Look at Dean. Look at his body. Imagine how it will feel when you touch it; how warm he is; the smoothness of his skin; all the lines and shapes of him you’ll get to stroke and feel and kiss.”

Cas did as instructed, eyes roaming over Dean’s body as he tried to imagine all the sensations Sam suggested.

The younger Winchester continued, his voice low and seductive. “Look at his cock and how big and thick it is. Look how it’s hard for you. Imagine what it tastes like; how it will feel in your mouth or filling up your ass. Touch it, if you like.”

Cas’ breathing was coming quick and heavy, and he could feel something stirring in his own groin as his gaze wandered down towards Dean’s crotch. It drifted there after pausing a moment on Dean’s face, who was staring down at Cas with darkened, lust-filled eyes. Cas felt something throb between his legs, and as his gaze settled on Dean’s cock he swiped his tongue over his chapped lips. Dean’s dick was stiff and flushed purple, curving backwards to hover over his abdomen while copious amounts of pre-come dribbled from the tip. There was a thick red vein on the underside that Cas could see throbbing in time with Dean’s pulse, and he thought the organ looked positively delicious.

With his fingers itching to feel it, he reached out and slowly wrapped his fist around Dean’s length. It was heavy and thick in his hand, although the velvet softness of the skin felt incredible beneath Cas’ fingers. Dean whimpered and sighed at the touch, and Cas felt a trembling breath leave his own lips as he became aware that his own dick had fully stiffened and was standing up hard against his stomach. He wondered if touching it would feel as good to him as it seemed to feel to Dean.

Dean whined and wriggled his hips, thrusting upwards in an attempt to get more friction from Cas’ touch. The angel didn’t quite know what to do, looking to Sam for help.

“You’re being very gentle with him,” the younger Winchester said. “Make sure you grip him nice and tight, and then stroke him hard and slow.”

Cas nodded, returning his eyes to settle on Dean’s face as he tightened his grip. Dean bit down on his lip in delight as he felt the pressure around his cock, and then Cas dragged his hand steadily along Dean’s length. Any words Dean might have shouted were lost through the gag, but Cas doubted they would have been coherent anyway as a cry of pure pleasure spilled from Dean’s throat. Encouraged, Cas stroked him again, feeling Dean’s cock throb beneath his hand. The responses he was getting were depraved and beautiful, and wanting Dean to enjoy it as much as possible, he began to pick up pace. He hadn’t been going for very long before Sam called him off.

“Okay, Cas, take it steady. I think you can take your hands off now. We want to make him last.”

Reluctantly, Cas pulled his fingers away from Dean’s cock, hearing Dean let out a horribly disappointed whine as he did so. “Are you sure he likes that?” he asked in concern.

“He knows that he’ll always get his orgasms if he’s a good boy and behaves himself,” Sam replied. “It’s more rewarding for him if he waits. Now, I think if he wants to come he needs a good fucking.”

Dean made another noise then and started to squirm on the bed, and a glance at his face showed that he was nodding enthusiastically.

Sam chuckled. “Alright, Cas. Dean’s got enough holes for us to share. He’s got this pretty little hole between his legs,” – Sam reached down to rub a finger against Dean’s opening – “And that gorgeous mouth of his. Now, Dean, how would you like it if I fucked your ass while Cas here fucked your face?”

Another cry and a nod showed that Dean would like it very much. Sam flashed Cas a grin. “Why don’t you get started while I prep him down here? That ring gag he’s got in is big enough for my cock, so it should fit yours. Go kneel over his face and put your cock in his mouth.”

This was all just so lewd and filthy it was making Cas’ head spin, and he loved every second of it. He did as Sam told him and repositioned himself so that he had his knees either side of Dean’s chest, while Sam spread Dean’s legs apart and started to stretch open his hole and rub some lube inside with his fingers. Dean moaned again.

Still figuring out what to do, Cas kept his eyes locked on Dean’s as he leaned forward to brace himself against the headboard and raised his hips to get in position. He managed to angle himself so that he’d be able to slide his cock down Dean’s throat, but he didn’t quite seem to realise he could use his hands to guide himself in and ended up dragging his cock over Dean’s face and chin before the tip slipped into his mouth. Dean seemed to enjoy that, eyes lighting up as he felt Cas’ precome smear across his cheeks. Or perhaps that was from the two slick fingers Sam currently had pressed inside him. Or both.

The moment that his cockhead passed Dean’s lips, Cas let out a gasp. The warm wetness of Dean’s mouth seemed to be drawing him in, eagerly pulling his cock deeper. He felt Dean’s tongue swiping at his length as he sank further in, and it was sinfully, blasphemously good. An angel should not be enjoying something this depraved this much, yet Cas found he was struggling to feel guilty. He closed his eyes and let himself slide deeper into the heat of Dean’s mouth as he ground his hips further down. The hunter’s tongue had been pushed to the back of his mouth by the gag, but he was still exercising it eagerly in his attempts to get more of the taste of Cas.

“Take it slow,” the angel heard Sam advise from between Dean’s legs, “He’s good at overcoming his gag reflex, but you need to give him time to adjust.”

Cas grunted his acknowledgement as he took care not to force himself down Dean’s throat too quickly. He pushed himself steadily inwards, head spinning with pleasure as Dean’s throat muscles clenched and then relaxed to accommodate him. He’d never imagined sex could feel this good. Especially not this kind of sex, but Dean appeared to be loving it as he hungrily swallowed the angel’s cock down. For Cas, the thrilled look in the hunter’s eyes was half the reward.

He was buried to the hilt before Dean finally began to show some signs of discomfort, and Cas felt his body jerk while his chest convulsed.

“He’s good at holding his breath too, but you’ll need to let him come up for air,” Sam offered helpfully again. “If you pull out enough when you’re thrusting, he’ll be able to breathe. I’m going to get inside him now, so follow my speed and don’t be afraid to get rough.”

Cas glanced briefly back over his shoulder to see Sam lining himself up at Dean’s entrance, and then turned to stare back down at Dean’s face with excitement coursing through him. Dean’s mouth was stretched wide and propped open with Cas’ cock buried inside him, the angel’s balls resting snug against Dean’s chin, and now he was about to have Sam’s length stuff him up even more fully. The sheen of sweat on his skin and pink flush beneath it showed the strain he was currently under, but it didn’t seem to abate his excitement.

For a moment, Cas locked eyes with Dean as they both braced for Sam’s next move, and then the hunter’s eyes squeezed closed and a grunt reverberated in his throat as his brother thrust into him. Cas cried out, feeling the hum of Dean’s moans vibrate along his length and tipping him closer to the edge. It didn’t take long for Sam to start moving, and Dean’s entire body shook and jerked in time with his thrusts. Cas didn’t need to set his own pace as the synchronised movements of Sam and Dean’s bodies did it for him, and he started to rock his hips to keep time. It felt fucking incredible, the way the tight heat of Dean’s throat repeatedly clenched around him as he bobbed in and out, and as Cas screwed his eyes shut in pleasure he could swear he saw stars. This was more heavenly than anything Heaven had to offer.

They kept going, building in speed and intensity until Cas was thrusting hard and rough down onto Dean’s face. Dean’s chest heaved as he desperately sucked in breaths down his nose each time Cas partially slid out, but he didn’t want any of it to stop. Sam’s thickness was buried deep inside his channel while his brother also had a tight fist pumping his cock, and that combined with the salty taste of Cas in his mouth was pure bliss. Dean couldn’t quite believe he was here and actually doing this like he’d dreamed of for so long: he had both of them. The two men he loved were here and giving him pleasure and he never had to choose between them. They both loved him. They both were happy to let each other love him. That thought caused so much happiness to swell in his chest that he thought he might burst.

It was after a few more hard, synchronised thrusts from them both that Dean was finally pushed past the tipping point, and he released the pressure building inside him in several forceful spurts that landed hot and sticky on Cas’ back. The angel was taken slightly by surprise when he felt it, but realising that meant they’d taken Dean to the pinnacle of pleasure, he felt a renewed thrill. Things weren’t over yet and Dean seemed eager to keep going as he still sucked hard at Cas’ cock buried in his mouth.

Sam was next to come, spilling his seed inside Dean with a cry before sliding out and collapsing down onto the bed. He watched as Cas finished, the angel bouncing frantically up and down on Dean’s face before he finally yelled and emptied his balls down Dean’s throat. Sam watched the way Dean’s throat muscles bobbed and clenched as he swallowed, and then Cas pulled his softening cock from Dean’s mouth and flopped down on the opposite side of the bed, panting.

Sam grinned. He was pleased by how much the angel had enjoyed his first time with Dean, but then his attention was immediately back on his brother. The ring gag was still forcing Dean’s mouth open and some of Cas’ come was dribbling out over his cheeks. Propping himself up on his elbow, Sam reached over to unfasten it and take it off.

“Good boy,” he praised as he pulled the plastic gag out of Dean’s mouth. “Did you swallow all of Cas’ come?” Dean was still flexing his jaw before he tried to speak again, but Sam smiled affectionately and reached up to stroke his cheek. “You got most of it, didn’t you? Well done, Dean.” He leaned down to press a kiss to Dean’s lips and lick away all the drops that Dean had missed. As he pulled back again he held Dean’s gaze, who was smiling blissfully, and then he looked over at Cas. “Did he do well, Cas?” Sam asked.

“He did _incredibly_ ,” Cas answered, looking somewhat blown away by the first orgasm he’d ever felt, all because of Dean.

Dean turned his head and grinned at him. “Thank you, Cas,” he said hoarsely, his throat still strained from the vigorous fucking. “Fuck, you tasted amazing. Thanks so much for doing this. I’ve wanted you to join in with us for so long, but I wouldn’t have known how to ask if it weren’t for Sammy.” He gave his brother a grateful smile, who grinned back before starting to untie Dean’s hands from the headboard.

“It was my pleasure, Dean,” Cas responded warmly. “Anything to make you happy. I would like to do this again, if you should wish.” He eased himself up off the bed then and stood up, still smiling as he drank in the happiness radiating from Dean. He couldn’t remember a time when he’d seen Dean looking so content, and amidst all the darkness that was currently building around them, he felt immensely pleased that he’d found a way to give Dean relief from it.

Noticing he was still somewhat sticky from Dean’s come coating his back, Cas used his angel powers to zap it away before he was about to restore his clothes. He was just turning away with the intention of getting dressed when he heard Sam speak again. “Cas?”

He turned back to stare at the two brothers lying on the bed, who were just now starting to climb under the covers. Sam looked puzzled while Dean seemed anxious. “Aren’t you staying for snuggles?” Sam asked.

“You both are going to bed now,” Cas stated in reply. “And Dean doesn’t like it when I watch him sleep.” That was at least one thing he’d learned about Dean’s preferences.

Or, at least, he thought he had.

“No, come on, Cas. Stay,” Dean pleaded, reaching out a hand to the angel to invite him under the covers. “If you’re going to fuck me I want to cuddle afterwards.”

Cas hesitated. He’d been preparing to leave once it was over to allow them both to rest, but with Dean making this offer, he thought there was nothing he’d rather do. “Alright,” he answered with a smile, lowering himself into bed beside Dean and pulling up the covers. “Do you want me to watch over you?”

“Yes, Cas,” Dean murmured. “If you want to. As long as you stay.”

This was a change from his usual attitude, Cas thought, but he supposed the sex _had_ changed things. And he thought it was for the better.

“When we do more extreme scenes, I’ll teach you about aftercare,” Sam said as he wrapped his hand around Dean’s waist from the other side. “That’s part of why Dean always likes to cuddle when we’re finished.”

Cas didn’t really know what that was, but it sounded good anyway. “I look forward to learning about it,” he said warmly as he snuggled closer to Dean, draping an arm over the hunter’s body and allowing Dean to nestle his head in the crook of his neck.

Dean smiled as he settled himself down in the warmth between their two bodies, feeling comforted by the fact he now had both of them to surround him. Everything else in their lives seemed to be falling apart and there was an apocalypse looming on the horizon, but at least, for now, this seemed to be going right. Sam was back, and this time Dean was determined not to lose him again, and now Cas was here with them and Dean wasn’t about to let either of them go. Darkness may be building all around them, closing in and its threat growing with each passing day, but at least in this bed in a small, shabby motel room where the three of them lay tangled up in each other, things were safe. In this tiny bubble Dean felt happy, and he felt loved. It was a bubble he never wanted to leave.


End file.
